Childhood and Alternate Personalities in Paracosm, Mythopoeia, Subcreation, Worldbuilding, Fictional Universe, and Fantasy World

The above terms are roughly synonymous, but may be used by different people and groups, who may or may not be familiar with their possible connection to childhood and alternate personalities.

The two types of fiction writing previously discussed here are Paracosm and Mythopoeia.

Paracosm is the only one that I know to have been studied as a feature of childhood.

I have discussed Mythopoeia as a function of alternate personalities, in that some alternate personalities like to make up stories, an attribute referred to as the mythopoetic function of alternate personalities.

Are writers who use any of the above (or similar) terms for their writing aware of the possible connection to childhood and alternate personalities?